Re: Schema design question as it pertains to performance

Benjamin Krajmalnik wrote:
> Kevin Grittner wrote:
>> Benjamin Krajmalnik wrote:

>>> I also assume that if no data has changed in an index, nothing
>>> is done when the record is updated as pertains to the
>>> particular index - am I correct in this assumption?
>>
>> No. [...] If any indexed column is updated, [...] it needs new
>> entries in all the indexes.

> That was my intent - if no column of an index changes in an
> update then no changes are done on the index.

I don't think you understood -- if any column referenced by any
index is updated, then all indexes must get a new entry for that
row whether or not they include that column. The new version of the
row will be at a new location, so new entries are needed in all
indexes to point to the new location.

I did *not* say that only indexes referencing the updated column
need a new entry.

-Kevin